1. National Engineering Research Center for Biomaterials, Sichuan University, Chengdu, P.R. China
2. Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, Shanghai, P.R. China
3. Department of Radiology, West China Hospital, Sichuan University, Chengdu, P.R. China
4. Department of Pathology, Case Western Reserve University, Cleveland, OH, USA
5. Department of Macromolecular Science, Case Western Reserve University, Cleveland, OH, USA
6. Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, USA